Patent GB-158179-A (GB)
Title: Improvements in a machine for making window envelope blanks
IPC: B31B19/00
Filed: 1920-06-18
Abstract: 158,179. Logan, J. June 18, 1920. Envelopes, making. - A machine for making " window " envelopes is provided with means for adjusting the patch-producing mechanism to suit blanks of different sizes, means for rendering the patch-producing mechanism inoperative in the absence of a blank in transit through the machine, and means wherebv the stack of blanks is moved into inoperative position when replenishing is necessary, the patchproducing mechanism being rendered inoperative at the same time. The blanks, previously cut to shape, are arranged in a pile 6, Fig. 4, on a rising table 7, and are lifted off one at a time bv an oscillating suction picker 8. The shaft 9, Fig. 3, which oscillates the picker, also carries an arm 14 which oscillates between two adjustable stops 16 on a sliding plate 17. The lower end of plate 17 carries a pawl 21 that operates a ratchet-wheel 24 on a shaft 25, which moves the pile table 7 upwards. The downward movement of the picker, and thus of the arm 14 and the plate 17, is controlled by the height of the pile of blanks, and when sufficient blanks have been removed, the movement of the plate 17 is sufficient to cause the pawl 21 to move the ratchet-wheel 24 and feed the rising table upwards, thus maintaining the top of the pile of blanks in position to be operated on by the picker. A second pawl 26, pivoted to the' frame, acts as a holding-pawl to prevent the ratchet-wheel 24 from turning backwards. A pin on the tail-piece of the pawl 26 engages in a slot a link 36 which is pivoted at its upper end to a hand-lever 38. By turning the lever, the pawl 26 can be lifted from the ratchet-wheel 24 and with it the pawl 21, thus permitting backward rotation of the ratchet-wheel, and the table falls under its own weight and the feed of the blanks ceases. A spring-operated latch 43 prevents the return of the lever 38 and, therefore, the resumption of the upward feed of the table until it is pushed back by the operator, when the link 36 is pulled upwards by a spring 49 and turns the lever 38 about its pivot 39. The feed continues until a stop on the table engages a tail-piece on the lever 38 thus turning the lever backwards and allowing the table to fall when the pile of blanks needs replenishment. A member 6<1>, Fig. 4, is inserted in the window aperture of the pile to maintain the blanks in alignment and to prevent the separation of more than one blank at a time. Each blank, as it is raised by the picker, is presented to a gripper 61 carried by a disc 5 on a shaft 4, and is carried by it until engaged by discs 62 which co-operate with the discs 5 to feed the blank forward between horizontal guides 64. The forward movement of the blanks is continued by discs 67<1>, and at the same time gum is applied in a band around the window aperture by gumming-dies 74 which are secured to a rotating shaft 67. These gummers 74 are supplied with gum from a box 72 by means of a transfer roll 70. The dies 74 are adjustable to suit window apertures of different sizes, and they co-operate with a cylinder 83 which is made in halves and provided with grooves to register with the gumming dies. The cylinder halves can be readily replaced by others to suit the various adjustments of the dies 74. In front of the guides 64 are feed-rolls 145, 183, the upper one 145 being provided with grippers 172 which receive a transparent patch, cut off from a web 114 by shears 154, and convey it to the blank, the rollers pressing it into position on the gummed portion of the blank, as it passes between the rolls. The web 114 is fed forward intermittently by a feed-roll 116 which is rotated in one direction by a ratchet-wheel and pawl operated by a rack 92, Fig. 3. The rack is pivoted on a block 90 adjustably secured in a slot in a crank arm 88 secured to the shaft 87 of the feed-roll 145. Thus by adjusting the position of the block 90, the stroke of the rack 92, and therefore the width of the transparent patch, can be varied as required. A device is provided to prevent the feed of a patch should the feed of blanks to the machine fail. This device consists of fingers 122 secured to a shaft 119, which is oscillated through a small arc and thus tends to swing the fingers in between the feed discs 5. This movement is prevented if a blank is held by the gripper 61, but should the supply of blanks fail, the fingers swing in between the discs 5, and the increased oscillation of the shaft 119 acts, through a lever 130, Fig. 3, and a sliding rod 132, to disengage the ratchet device which feeds the web of the patch material, and the feed is stopped until a blank is again fed into the machine.